Problem with Value in DataGridViewComboBoxColumn

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I have:

protected void InitControls()
{
gvProfile.AutoGenerateColumns = false;

DataTable dtProfile = new DataTable("KFS");
// dodajemy kolumny
foreach(DataGridViewColumn dc in gvProfile.Columns) {
DataColumn ndc = new DataColumn();
ndc.ColumnName = dc.Name;
dtProfile.Columns.Add(ndc);
}

foreach (KeyValuePair<string, stringkfs in dicKFS) {
DataRow drow = dtProfile.NewRow();
drow["KFS_KOD"] = kfs.Key;
drow["KFS_NAZWA"] = kfs.Value;
dtProfile.Rows.Add(drow);
}

DataTable dtGFS = new DataTable("GFS");

// i ustawiamy liste dla Combo
List<ItemlItem = new List<Item>();
foreach (KeyValuePair<string, stringgfs in dicGFS) {
Item item = new Item();
item.ItemID = Convert.ToInt32(gfs.Key);
item.ItemName = gfs.Value;
lItem.Add(item);
}
GFS.DisplayMember = "ItemName";
GFS.ValueMember = "ItemID";
GFS.DataPropertyName = "Item";
GFS.DataSource = lItem;

gvProfile.DataSource = dtProfile;

if(_iPXX != -1) SetData(_iPXX);
}
when Item is:

class Item
{
private int itemID;
private string itemName;

public int ItemID
{
get { return this.itemID; }
set { this.itemID = value; }
}

public string ItemName
{
get { return this.itemName; }
set { this.itemName = value; }
}
}

When I'm trying after Init set:

dgvr.Cells["GFS"].Value = 2;

Combo doesn't react on my setting.
How can I set DataGridViewComboBoxColumn with effect ?